In order to rely upon an accelerometer in an electromechanical system, the health of the accelerometer should be ensured. In certain electromechanical systems, such as aircraft and spacecraft, accurate accelerometer operation may be critical. For instance, sensor system malfunction is a significant contributor to propulsion in-flight shutdowns (IFSDs), which can lead to aircraft and spacecraft accidents, particularly when the issue is compounded with an inappropriate crew response.
Previous techniques for monitoring accelerometer health include simply observing the operation of the sensor. Anomalies and inconsistencies in the sensor values suggest sensor failure. Physically inspecting the sensor could confirm a fault. Voting methods utilizing multiple sensors measuring the same parameter could potentially mitigate the effect of a small number of faulty sensors. However, multiple sensor failures could be catastrophic in a voting scenario.
Physically observing the sensor is often not possible during operation of the electromechanical system, and in-flight testing limits sensor access. Inspection and repair of faulty integrated sensor systems could be difficult and costly in terms of both time and money. Slow diagnosis is also an issue. Automatically and immediately addressing a faulty sensor by removing it from voting or use by other systems is of a high priority in critical situations.
Previously designed, relatively large self-diagnostic accelerometers (SDAs) used a large signal analyzer, which required increased space and power requirements. These SDAs also required attached computers to post-processes the diagnostic data in order to determine the health of the sensor. Thus, the health determination wasn't performed in real time or near-real time. Accordingly, an improved SDA system may be beneficial.